This invention is directed to customer premises equipment which enables a user's personal computer to receive downstream information over a cable television channel while permitting upstream communications over a separate communication channel such as over the public switched telephone network.
There is an increasing need to provide higher data transfer rates especially from service providers to end users in view of multimedia applications. For example, it requires a substantial amount of data to define a high resolution color picture to be displayed on the monitor of a user's personal computer, and an even greater amount if the picture is to be animated. Conventional modems operating over the public switched telephone network are able to achieve data transfer speeds approaching 30 kilobits per second. Such data rates are too slow to accommodate multimedia applications. In many applications the computer user transmits relatively small amounts of information consisting primarily of requests for information to a service provider and thus, a lower speed channel can be utilized to provide the upstream communications between the user and the service provider without noticeable delays.
In U.S. Pat. No. 4,862,268, a control system for addressable cable television is disclosed which permits the transmission of data using a video format. Data is transmitted in a video format during the vertical blanking interval of a normal television signal.
An interactive videotex system is described in U.S. Pat. No. 5,093,718 wherein users are provided with an increased speed of delivery of information. A plurality of nodes is distributed along a cable TV system wherein each node serves a relatively small group of users and contains in its memory substantially all information needed to communicate with users. A central computer or processing center provides data to the regional nodes and provides updates for information stored at the nodes. Thus, a relatively small group of users is supported by each node and thereby provides increased speed in which information can be delivered to the user.
Broadband RF signals are combined with baseband signals on a single distribution cable as described in U.S. Pat. No. 5,255,267. RF signals above 35 megahertz are simultaneously present with baseband signal below 25 megahertz on a single cable. From a single personal computer node, baseband signals are propagated in both directions while permitting the RF signals to propagate only in a single direction from the RF head-end equipment.
A hybrid access system has been proposed to provide remote computer users with a high-speed (10 megabits per second) access to the Internet network for high-speed downstream data transfer to the users while simultaneously permitting independent lower speed upstream channels to be utilized to transmit user requests for information. It is understood that such a :product has been marketed by Hybrid Networks, Inc.
Cable modems operating at up to 10 megabits per second over cable television cables are available from Zenith Electronics and General Instrument Corporation. Thus, there exists a capability for encoding conventional digital information over a cable television channel.
However, there exists a need to provide higher speed data communications to a user's personal computer in an effective and efficient manner, especially in the downstream direction. Preferably, existing resources should be utilized.